1、趋势类词汇
　　上升动词类： increase, go up, rise up, grow up, jump up, surge, shoot up, keep an upward tendency
　　下降动词类： decrease, go down, decline, fall down, drop, sink, dip, keep a downward tendency
　　波动动词类： fluctuate
　　持平动词类： remain the same, stabilize, remain stable, remain constant
　　修饰动词的副词： slightly 轻微地， slowly 缓慢地， gradually 逐渐地， steadily 稳定地， rapidly 迅速地， moderately 温和地， 轻微地， significantly 明显地， sharply 明显地， dramatically急剧地， drastically 急剧地
　　上升名词类： increase, rise, growth, jump, surge
　　下降名词类： decrease, decline, fall, reduction, drop
　　波动名词类： fluctuation
　　修饰名词的形容词： slight, slow, gradual, steady, rapid, moderate, significant, sharp, dramatic, drastic
　　2、极值类词汇和表达
　　最高点： reach the peak/top/highest point
　　Increase to the peak/top/highest point(所有上升类的动词都可以替换掉increase)
　　最低点： reach the bottom/lowest point
　　drop to the bottom/lowest point(所有下降类的动词都可以替换掉drop)
　　占的最多： occupy/make up/take up/account for the largest proportion/number/percentage of …
　　占的最少： occupy/make up/take up/account for the smallest proportion/number/percentage of …
　　3、倍数的表达方式
　　Double 是两倍/大一倍
　　Increase/decrease three times 增长/减少了三倍
　　4、大约的表达方式
　　About/around + 数字
　　数字 + or so
　　Approximately + 数字
　　5、常用的小作文的趋势句式表达
　　句式一： 变化主体/图画中主体+趋势动词+副词+时间区间
　　Eg: The number of aged people over 65 increased significantly from 1940-2000.
　　The number of aged people over 65 dropped slightly from 1960-1980.
　　The number of aged people over 65 fluctuated between 1 million and 1.2 million from 1940-1950.
　　The number of aged people over 65 remained stable from 1930-1940.
　　句式二： There be + 形容词 + 表示趋势的名词 + in+ 变化的主体+ 时间区间
　　Eg: There was an significant increase in the number of aged people over 65 from 1940-2000.
　　There was a slight decline in the number of aged people over 65 from 1960-1980.
　　There was a fluctuation between 1 million and 1.2 million from 1940-1950.